Presently, NMR analysis devices, which analyze a specimen using a static magnetic field produced by a superconducting magnet, are known.
For example, Patent Literature 1 discloses an analysis device that includes a superconducting magnet, a liquid helium tank that contains a superconducting magnet and liquid helium that cools the superconducting magnet, a liquid nitrogen tank that surrounds the liquid helium tank and contains liquid nitrogen, a vacuum container that covers the liquid helium tank and the liquid nitrogen tank, and a two-stage chiller that is attached so as to communicate with the liquid helium tank and the liquid nitrogen tank.
In the analysis device disclosed in Patent Literature 1, penetration of external heat into the liquid helium tank is suppressed by the cold of liquid nitrogen contained in the liquid nitrogen tank. Also in the analysis device disclosed in Patent Literature 1, liquid helium is re-condensed using a low-temperature side stage of the two-stage chiller, and liquid nitrogen is re-condensed using a high-temperature side stage of the two-stage chiller.
Specifically, a liquid helium re-condensation tank is provided for the low-temperature side stage of the two-stage chiller. A helium gas from the liquid helium tank is received in the liquid helium re-condensation tank. A liquid nitrogen re-condensation tank is provided for the high-temperature side stage of the two-stage chiller using a heat transfer rod. A nitrogen gas from the liquid nitrogen tank is received in the liquid nitrogen re-condensation tank.
However, in order to cool the superconducting magnet, the analysis device disclosed in Patent Literature 1 needs to include not only the liquid helium tank but also the liquid nitrogen tank. Thus, it is difficult to reduce the overall size of the analysis device.
The liquid nitrogen tank may be omitted from the analysis device. In this case, however, there arises a problem on how to suppress penetration of external heat into the liquid helium tank.